在本論文研究當中，我們成功的利用射頻磁控濺鍍沉積技術，插入高品質超薄型二氧化鉿與三氧化二鋁薄膜，來研製雙層式閘極介電層之氮化鋁鎵/氮化鎵金屬-氧化物-半導體高電子遷移率電晶體。我們使用射頻磁控濺鍍法來沉積二氧化鉿薄膜，當作元件的閘極介電層，目的為降低元件閘極漏電流以及提升崩潰電壓的特性，除此之外，插入三氧化二鋁薄膜，藉由其高能隙以及高崩潰電壓的材料特性，能夠進一步有效的抑制閘極漏電流的出現與提升截止狀態的崩潰電壓，並且降低介面缺陷密度。
本研究論文當中，藉由比較傳統型氮化鋁鎵/氮化鎵高電子遷移率電晶體以及氮化鋁鎵/氮化鎵金屬-氧化物-半導體高電子遷移率電晶體，成功的使得氮化鋁鎵/氮化鎵雙層式-金屬-氧化物-半導體高電子遷移率電晶體的閘極漏電流降低三至五個數量級，並且成功的提高崩潰電壓70伏特，而且其他的電性也都有所增加。
本研究論文使用射頻濺鍍技術，沉積二氧化鉿薄膜以及三氧化二鋁薄膜，成功的於實驗當中製備出雙層式-金屬-氧化物-半導體之高電子遷移率電晶體。在閘極電壓對源極電壓為 3 V的時候(Vgs = 3 V)，最大的汲極電流密度成功提升至 720 (mA / mm)，而最大的外部轉導值達到132.4 (mS/mm)，而臨界電壓成功的提升至 -2.32 V，而在選取閘極電壓為-6 V( Vg = -6 V)之下，閘極漏電流有效地降低至1.712 × 10-8 (mA/mm)，而在汲極對源極的電壓為6 V(Vds = 6 V)的條件下，電流開關比提升至2.039 × 1010，以及次臨界擺幅有效降低至 81 (mV/dec)，而三端崩潰電壓提升至120 V，而最大的電容值為1332 ( nF/cm2 )，而最大的震盪頻率為8.3 (GHz)。

SUMMARY
In this study, AlGaN/GaN double-metal-oxide-semiconductor high electron mobility transistors (Double MOS-HEMTs) with stacked high quality ultra-thin HfO2/Al2O3 as gate dielectric layer have been successfully fabricated by the RF-sputtered technique. We have used RF sputter to deposit HfO2 thin film as the gate dielectric layer in order to reduce the gate leakage current and enhance the breakdown voltage performance. In addition, we have used Al2O3 dielectric which has high bandgap and high off-state breakdown voltage can further effectively suppress gate leakage current and increase off-state breakdown voltage and decrease interface state density.
In this work, the Double MOS-HEMTs of the gate leakage current is successfully reduced by 3-5 orders of magnitude, and the off-state breakdown voltage increased by approximately 70V compared with conventional AlGaN/GaN high electron mobility transistors and AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors with a high-k HfO2 dielectric as gate oxide layer. Other electrical performances are also enhanced obviously.
In this study, AlGaN/GaN double-metal-oxide-semiconductor high electron mobility transistors (Double MOS-HEMTs) with stacked high quality ultra-thin HfO2/Al2O3 as gate dielectric layer have been successfully fabricated by the RF-sputtered technique. In this work, we have demonstrated the Double MOS-HEMTs threshold voltage successfully shifted to -2.32 V with the maximum drain current density is successfully improved to 720 mA/mm at VGS = 3 V. The transfer characteristics show a maximum transconductance characteristics of 132.4 mS/mm, a subthreshold swing is effectively reduced to 81 mV/dec, and an on/off ratio reaches 2.039 × 1010 at VDS = 6 V. The gate leakage current is effectively reduced to 1.712 × 10-8 mA/mm at VGS = -6 V and the three-terminal breakdown voltage reaches 120 V. The maximum capacitance reaches 1332 nF/cm2, and a maximum oscillation frequency is 8.3 GHz.

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